She's my little shared coupe

Zipcar and Flexcar, the biggest players in the car-sharing business, recently announced a merger with the goal of becoming profitable within a year and ultimately launching an IPO. The news was not exactly treated to a chorus on huzzahs in the business press. Zipcar and Flexcar -- based in the respective guilty-liberal/indie-culture capitals of Cambridge, Mass., and Seattle -- largely have been viewed as the college radio of the car industry: cool, influential, trendy, but ultimately unthreatening to the 24/7 freedom of personal car ownership.

Car sharing, however, offers a new and seductive form of freedom, one based on the refusal of direct ownership and the liability that entails. The key to the Zip-Flex business model is that the actual car is not all that important. It is really just a means to an end. It's a transportation appliance, a node in a system made possible by the Internet.

The entire process is simple. Once an approved licensed driver pays his dues and becomes a member, he logs in to the company's website to select where he wants to pick up a car and how long he wants to use it. The membership card is a magnetic key that unlocks the doors; the keys are in the glove compartment. Regular users pay about $10 an hour on average, which covers gas, maintenance and insurance and can be automatically charged to a credit card.

The hippie, communitarian lineage is obvious. But whereas 30 years ago a cluster of lefty do-gooders might pass around the key to a single wheezing VW bus, today's car sharers are tidily segregated by technology. I've been using Flexcar in downtown Los Angeles for two years, and in all that time, I've never seen nor interacted with another member. I've never spoken to a Flexcar representative on the phone. Yet the system has been immensely reliable. I reserve a neat, white Honda Civic hybrid online, pick it up down the street at the appointed hour and, after my errand or outing, return it to its designated spot in a hotel parking structure. The system is smooth, impersonal and inexpensive -- the antithesis of the dreary airport rental-car counter, with its yawning lines and niggling forms.

Understandably, Zipcar and Flexcar have found the most success in places where walking is still an important feature of the transportation grid -- Washington, Boston, San Francisco and university towns such as Ann Arbor, Mich. Unfortunately, the very fact of the Zip-Flex merger, announced Oct. 31, bodes poorly for the idea that car sharing might finally be ready to thrive beyond its niche of eco-conscious city-dwellers and impoverished undergrads. Neither Zipcar nor Flexcar is especially large; combined, they'll be in about 50 cities. Their marriage means that both are probably more worried about survival than profits.

Still, car sharing, turbocharged by the Internet, has let the genie of mobility systems out of the bottle. Why bother owning the entire apparatus of movement when you can instead simply check in and out of the transportation matrix? In many cases, freedom from vehicle ownership should allow people to put their money into investments that do not lose value as soon as they are driven off the dealer's lot.

Over time, regardless of whether the Zip-Flex merger succeeds or fails, transportation systems will begin to displace the crude mechanics of individual ownership. Anyone who leases a car has already gotten a taste, albeit with no financial upside. Fractional-ownership plans for a private jet are the same sort of deal. (Imagine if someone paid to drive your car, thereby monetizing the many idle hours your vehicle spends costing you cash.) Currently, however, our larger transportation grid is barely integrated. Airlines don't talk to railroads; NetJets doesn't talk to Metrolink.

Individual ownership of something as complicated and labor intensive as transportation gradually will be supplanted by collective ownership of (or membership in) a vast system that provides abundant mobility options with all of the carbon-credit upsides and none of the congestion-charge headaches. The personal automobile may continue to have a place of pride in the driveway, but it won't be at the top of the food chain anymore. Transportation will finally achieve true mass distribution. It will become a commodity. Every innovation, from electric commuter cars to jet packs to personal submarines and rocket-assisted rickshaws, will make it less expensive and more democratic. And in the end, we will have car sharing, whatever becomes of it, to thank for cracking the code.